Dennis J. “Denny” O’Neil is an American comic book writer and editor, principally for Marvel Comics and DC Comics in the 1960s, 1970s, 1980s, and 1990s, and Group Editor for the Batman family of books until his retirement.

His best-known works include Green Lantern/Green Arrow and Batman with Neal Adams, The Shadow with Mike Kaluta and The Question with Denys Cowan, all of which were hailed for their sophisticated stories that expanded the artistic potential of the mainstream portion of the medium. As an editor, he is principally known for editing the various Batman titles. As of 2012, he sits on the board of directors of the charity The Hero Initiative and serves on its Disbursement Committee.

When Roy Thomas left DC Comics to work for Stan Lee at Marvel Comics he suggested that O’Neil take the Marvel writer’s test, which involved adding dialogue to a wordless four-page excerpt of a Fantastic Four comic; and O’Neil’s entry impressed Lee enough to offer him a job.

When Marvel’s expansion made it impossible for Lee to continue writing the company’s entire line of books, Lee passed as much on to Roy Thomas as he could, but still needed writers, so O’Neil took the reins for a short-term run of Doctor Strange stories in Strange Tales, penning six issues. He also wrote dialog for such titles as Rawhide Kid and Millie the Model, as well as scripting the final 13 pages of Daredevil #18 over a plot by Lee, when Lee went on vacation.

While working for Marvel Comics he helped write the original character concept for the Transformers, and is credited as the person who named Optimus Prime.

The available jobs writing for Marvel petered out fairly quickly, and O’Neil took a job with Charlton Comics under the pseudonym of Sergius O’Shaugnessy. There he received regular work for a year and a half from Charlton’s editor Dick Giordano.

In 1968 Dick Giordano was offered an editorial position at DC Comics and took a number of Charlton freelancers with him, including O’Neil. Charlton talent arrived at DC from a different culture of comics. At DC, the office seemed like a snapshot from 1950, with a crowd of short-haired men in white shirts and ties. The jeans-wearing, hippy trended Charlton crowd visibly represented a different generation.

O’Neil’s first assignments involved two strategies for bolstering DC’s sales. One approach centered on the creation of new characters, and O’Neil scripted several issues of Beware the Creeper, a series starring a new hero, The Creeper, created by artist Steve Ditko. From there, DC moved O’Neil to Wonder Woman and Justice League of America. With artist Mike Sekowsky, he took away Wonder Woman’s powers, exiled her from the Amazon community, and set her off, uncostumed, into international intrigues with her blind mentor, the dubiously-named I Ching. These changes did not sit well with Wonder Woman’s older fans, particularly feminists, and O’Neil acknowledged that de-powering DC’s most well-known superheroine had unintentionally alienated readers. In Justice League, he had more success, introducing into that title the first socially and politically themed stories, setting the stage for later work on Green Lantern/Green Arrow. He and artist Dick Dillin made several changes to the membership of the JLA by removing founding members the Martian Manhunter and Wonder Woman.

Following the lead set by Bob Haney and Neal Adams in a Brave and the Bold story that visually redefined Green Arrow into the version that appeared in comics between 1969 and 1986, O’Neil stripped him of his wealth and playboy status, making him an urban hero. This redefinition would culminate in the character that appeared in Green Lantern/Green Arrow, with many stories also drawn by Adams, a socially conscious, left-wing creation that effectively took over Green Lantern’s book to use him as a foil and straw man in sounding out the political concepts that would define that work. It was during this period that the most famous Green Arrow story appeared, in Green Lantern #85-86, when it was revealed that Green Arrow’s ward Speedy was addicted to heroin.

O’Neil’s 1970s run on the Batman titles, under the direction of editor Julius Schwartz, is perhaps his best-known endeavor, getting back to the character’s darker roots after a period dominated by the campiness of the 1960s TV series. Comics historian Les Daniels observed that “O’Neil’s interpretation of Batman as a vengeful obsessive-compulsive, which he modestly describes as a return to the roots, was actually an act of creative imagination that has influenced every subsequent version of the Dark Knight.” O’Neil and Adams’ creation Ra’s al Ghul was introduced in the story “Daughter of the Demon” in Batman #232 (June 1971) O’Neil and artist Bob Brown also created Talia al Ghul. During this period, O’Neil frequently teamed up with his regular collaborator Adams (with Giordano often assisting on inks) on a number of memorable issues of both Batman and Detective Comics. The Joker was revitalized in “The Joker’s Five-Way Revenge!” in Batman #251 (Sept. 1973), a landmark story bringing the character back to his roots as a homicidal maniac who murders people on a whim and delights in his mayhem. O’Neil and Giordano created the Batman supporting character Leslie Thompkins in the story “There Is No Hope in Crime Alley” appearing in Detective Comics #457 (March 1976).

When Julius Schwartz became the editor of Superman with issue #233 (Jan. 1971), he had O’Neil and artist Curt Swan streamline the Superman mythos, starting with the elimination of Kryptonite. In 1973, O’Neil wrote revivals of two characters for which DC had recently acquired the publishing rights. A new series featuring the original Captain Marvel was launched with a February cover date and featured art by the character’s original artist C. C. Beck. Later that same year, O’Neil and artist Michael Kaluta produced an “atmospheric interpretation” of the 1930s pulp hero in The Shadow series. In 1975, O’Neil wrote a comic book adaptation of the 1930s hero The Avenger. A revival of the Green Lantern title in 1976 was launched by O’Neil and artist Mike Grell. Reuniting with Adams, O’Neil co-wrote the oversize Superman vs. Muhammad Ali (1978) which Adams has called a personal favorite of their collaborations.

After returning to DC Comics in 1986, he became the editor of the various Batman titles and served in that capacity until 2000. In February 1987, O’Neil began writing The Question ongoing series which was primarily drawn by Denys Cowan. The Batman: Legends of the Dark Knight series began in 1989 with the five-part “Shaman” storyline by O’Neil and artist Ed Hannigan. Armageddon 2001 was a 1991 crossover event storyline. It ran through a self-titled, two issue limited series and most of the annuals DC published that year from May through October. Each participating annual explored potential possible futures for its main characters. The series was written by O’Neil and Archie Goodwin and drawn by Dan Jurgens. The character Azrael was created by O’Neil and artist Joe Quesada in the Batman: Sword of Azrael miniseries in 1992.

Upon O’Neil’s return to Marvel Comics in 1980, he took on the scripting chores for The Amazing Spider-Man, which he did for a year. He was the regular scripter for Iron Man from 1982–1986, and Daredevil, from 1983–1985. During his run on Iron Man, O’Neil introduced Obadiah Stane, later the Iron Monger, plunged Tony Stark back into alcoholism, turned Jim Rhodes into Iron Man, and created the Silver Centurion armor. O’Neil’s run on Daredevil bridged the gap between Frank Miller’s two runs on the title, usually with David Mazzucchelli as artist. He introduced Yuriko Oyama during his stint, who would later become the popular X-Men villain Lady Deathstrike.

O’Neil has written several novels, comics, short stories, reviews and teleplays, including the novelizations of the films Batman Begins and The Dark Knight. Under the pseudonym Jim Dennis, O’Neil scripted a series of novels about a kung fu character named Richard Dragon, and later adapted those novels to comic book form for DC.

O’Neil wrote a weekly column for ComicMix until October 2008.

Joining Marvel’s editorial staff in 1980, O’Neil edited Daredevil during Frank Miller’s run as writer/artist. He fired writer Roger McKenzie so that Miller could both write and pencil Daredevil, a decision which then-Marvel editor-in-chief Jim Shooter says saved the series from cancellation. In the early to mid-1980s, O’Neil edited such Marvel titles as Alpha Flight, Power Man and Iron Fist, G.I. Joe, and Moon Knight.

According to Bob Budiansky, O’Neil came up with the name for the Transformer Optimus Prime, leader of the Autobots.

In 1986, O’Neil moved over to DC as an editor, becoming group editor for the company’s Batman titles. Speaking about his role in the death of character Jason Todd, O’Neil remarked:

It changed my mind about what I do for a living. Superman and Batman have been in continuous publication for over half a century, and it’s never been true of any fictional construct before. These characters have a lot more weight than the hero of a popular sitcom that lasts maybe four years. They have become postindustrial folklore, and part of this job is to be the custodian of folk figures. Everybody on Earth knows Batman and Robin.

O’Neil spent several years in the late nineties teaching a Writing for the Comics course at Manhattan’s School of Visual Arts, sometimes sharing duties with fellow comic book writer John Ostrander.

O’Neil’s work has won him a great deal of recognition in the comics industry, including the Shazam Awards for Best Continuing Feature Green Lantern/Green Arrow, Best Individual Story for “No Evil Shall Escape My Sight” in Green Lantern #76 (with Neal Adams), for Best Writer (Dramatic Division) in 1970 for Green Lantern, Batman, Superman, and other titles, and Best Individual Story for “Snowbirds Don’t Fly” in Green Lantern #85 (with Neal Adams) in 1971. In 1985, DC Comics named O’Neil as one of the honorees in the company’s 50th anniversary publication Fifty Who Made DC Great.